From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B502C1B0D9 for ; Mon, 14 Dec 2020 05:54:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B17A5229EF for ; Mon, 14 Dec 2020 05:54:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405889AbgLNFyg (ORCPT ); Mon, 14 Dec 2020 00:54:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50418 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406070AbgLNFy1 (ORCPT ); Mon, 14 Dec 2020 00:54:27 -0500 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27373C0613CF; Sun, 13 Dec 2020 21:53:47 -0800 (PST) Received: by mail-pj1-x1044.google.com with SMTP id p21so4331724pjv.0; Sun, 13 Dec 2020 21:53:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:cc:references:in-reply-to:mime-version :message-id:content-transfer-encoding; bh=NqlRmCcPn1hL++OXjNViT5mh7QFqv3t1WGYe29FT4N0=; b=OU2rJ+vKQqYkt0zKH+mic4jtuIu5GNnbiOiORyCT+A09h9fwQVJL2rUCwqMLf/iuvX 9ZevRGt+gw00mt8IToXd9T4cMAxsajKDwuMJ3rHqXjunXGxeic1yFQN6+BViqPc3jG7q EHj/gFwO3qj7id91+Aj8fVSteXlSH1WbD3B2ObgpDbyX8867Mu/Zc/nZkwqf3u3MeTWQ GUeAIzmYgifLuP+jbiHnVevOjjad1G3brEZa0Wsx/7D97e94816uenMsagjZ4YzhON5a kRKy8l2UgGjX8qjPTJPf7BQTJmLavUTfJA2Wx7MZfep/q6BF6KkbSj6Q3l16mESODtcO iBEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:subject:to:cc:references:in-reply-to :mime-version:message-id:content-transfer-encoding; bh=NqlRmCcPn1hL++OXjNViT5mh7QFqv3t1WGYe29FT4N0=; b=ShmvmuBd0/4q349HXDI8yRIxn4N5aMv7gisZrwKsG4FZCPeqDUTMV5tdlQX/ybiCC1 kE3saPlMBsSRtfU3BLe77r1Gnd5e5vwjybzpAmbL1UKF0Xq427mocJlx0BYqXiwaBrsS Cliq5B17Bk6w5zxFgyjbAKG8Kh4fNb61SLyCs6vrqSFPdoKmw5vkw083b8OdpGf/GYBZ qc/86XZipWlkO2pi9zBno7BKaB7RNh9A7fy7+ou48WkT6ov9AhW33ROwJjztVev0k88S sEUaUB3m3b1WJ2IsvM0smpJDG+dnfHUQUsQUTSd31K8Yg23IIEA1qEOpkK+0AzBSmw08 ol9A== X-Gm-Message-State: AOAM5327PZUnpFxzpXqfL6MgaT2gBfqudDERrkD4BS1w5Udw9fPGS/OU +4B70DiVHOsRrHAM7EC+MU4sTFDgDvk= X-Google-Smtp-Source: ABdhPJwf3b9TbWiNhAad5JT/pHJRZTvkOiZpc3S6PMZHL+xFsjBjgGypaMaAxP447A+pDMg1mPexiA== X-Received: by 2002:a17:90a:fb92:: with SMTP id cp18mr23372071pjb.203.1607925226593; Sun, 13 Dec 2020 21:53:46 -0800 (PST) Received: from localhost ([220.240.228.148]) by smtp.gmail.com with ESMTPSA id v126sm17639802pfb.137.2020.12.13.21.53.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Dec 2020 21:53:45 -0800 (PST) Date: Mon, 14 Dec 2020 15:53:40 +1000 From: Nicholas Piggin Subject: Re: [PATCH 2/8] x86: use exit_lazy_tlb rather than membarrier_mm_sync_core_before_usermode To: Andy Lutomirski Cc: Anton Blanchard , Arnd Bergmann , linux-arch , LKML , Linux-MM , linuxppc-dev , Mathieu Desnoyers , Peter Zijlstra , X86 ML References: <1607152918.fkgmomgfw9.astroid@bobo.none> <116A6B40-C77B-4B6A-897B-18342CD62CEC@amacapital.net> <1607209402.fogfsh8ov4.astroid@bobo.none> <1607224014.8xeujbleij.astroid@bobo.none> <1607918323.6muyu2l982.astroid@bobo.none> In-Reply-To: <1607918323.6muyu2l982.astroid@bobo.none> MIME-Version: 1.0 Message-Id: <1607924970.hd6nln4qe5.astroid@bobo.none> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Excerpts from Nicholas Piggin's message of December 14, 2020 2:07 pm: > Excerpts from Andy Lutomirski's message of December 11, 2020 10:11 am: >>> On Dec 5, 2020, at 7:59 PM, Nicholas Piggin wrote: >>> >>=20 >>> I'm still going to persue shoot-lazies for the merge window. As you >>> see it's about a dozen lines and a if (IS_ENABLED(... in core code. >>> Your change is common code, but a significant complexity (which >>> affects all archs) so needs a lot more review and testing at this >>> point. >>=20 >> I don't think it's ready for this merge window. >=20 > Yes next one I meant (aka this one for development perspective :)). >=20 >> I read the early >> patches again, and I think they make the membarrier code worse, not >> better. >=20 > Mathieu and I disagree, so we are at an impasse. Well actually not really, I went and cut out the exit_lazy_tlb stuff from the patch series, those are better to be untangled anyway. I think=20 an earlier version had something in exit_lazy_tlb for the mm refcounting=20 change but it's not required now anyway. I'll split them out and just work on the shoot lazies series for now, I might revisit exit_lazy_tlb after the dust settles from that and the current membarrier changes. I'll test and repost shortly. Thanks, Nick